Liteon Semiconductor Corporation
LSP5502
2A Synchronous Rectified Step Down DC/DC Converter
FEATURES
2A Output Current
Wide 4.5V to 30V Operating Input Range
Integrated 100mΩ Power MOSFET Switches
Output Adjustable from 0.925V to 28V
Up to 96% Efficiency
Programmable Soft-Start
Stable with Low ESR Ceramic Output Capacitors
Fixed 400KHz Frequency
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
8-Pin SOP Package
GENERAL DESCRIPTION
The LSP5502 is a monolithic synchronous buck
regulator. The device integrates 100mΩ MOSFETS
that provide 2A continuous load cur-rent over a wide
operating input voltage of 4.5V to 30V. Current mode
control provides fast transient response and
cycle-by-cycle cur-rent limit.
An adjustable soft-start prevents inrush current at turn
on. In shutdown mode, the supply cur-rent drops
below 1µA.
This device, available in an 8-pin SOP package,
provides a very compact system solution with minimal
reliance on external components.
TYPICAL APPLICATION
Distributed Power Systems
Networking Systems
FPGA, DSP, ASIC Power Supplies
Green Electronics/ Appliances
Notebook Computers
PIN ASSIGNMENT
(Top View)
PIN DESCRIPTION
Name
BS
IN
SW
G
FB
COMP
EN
SS
No.
1
2
3
4
5
6
7
8
Description
Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver.
Connect a 0.1uF capacitor between BS and SW.
Input Supply. Bypass this pin to G with a low ESR capacitor. See Input Capacitor
in the Application Information section.
Switch Output. Connect this pin to the switching end of the inductor.
Ground.
Feedback Input. The voltage at this pin is regulated to 0.925V. Connect to the
resistor divider between output and ground to set output voltage.
Compensation Pin. See Stability Compensation in the Application Information
section.
Enable Input. When higher than 2.5V, this pin turns the IC on. When lower than
1.3V, this pin turns the IC off. Output voltage is discharged when the IC is off.
When left unconnected, EN is pulled high internally.
Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from
SS to GND to set the soft-start period. A 0.1µF capacitor sets the soft-start period
to 15ms. To disable the soft-start feature, leave SS unconnected.
1/11
Rev1.1
LITEON [ LITE-ON TECHNOLOGY CORPORATION ]
